Starter gearing



March 27, 1934.

M. P. WHITNEY 1,952,645

STARTER GEARING Filed April 21, 1932 2 Sheets-Sheet 1 I 11v VENTOR fi mEs: v r B Y 6 M A TTORNEY March 27, 1934. p. wHlTNEY I 1,952,645

STARTER GEARING Q Filed April 21, 1932 2 Sheets-Sheet 2 3% 4 (NVENTORTflaur' Pw/u'tney hV/rmsssx [0d] I A OR/VEY Patented Mar. 27, 1934UNITED STATES PATENT OFFICE STARTER GEARING Application April 21, 1932,Serial No. 606,743

18 Claims.

The present invention relates to starter gearing. and more particularlyto a starter drive of the type in which a pinion is automaticallytraversed into and out of engagement with an engine member.

The development of small bore multi-cylinder automotive engines and oflower car bodies and engine mountings have contributed to the tendencyto decrease the size of engine flywheels. At

the same time the high compression ratios now used require high crankingtorque so that if a small starting motor is to be used, a high gearreduction to the engine flywheel is necessary.

It is an object of the present invention to provide a novel drive ofthis type which is small and compact and permits the use of a starterpinion of small diameter whereby a suitable gear reduction may be usedwith a small flywheel gear.

Another object is to provide such a device 'in- 0 cluding a yieldingdriving connection which is small and light in construction while beingamply strong to transmit the required torque.

Another object is to provide such a device embodying novel provisionsfor enforcing meshing of the pinion with the flywheel gear in case a.tooth of the pinion should abut end to end with a tooth of the gear.

A further object is to provide such a device embodying novel provisionsfor preventing rebounding of the pinion toward the engine gear when itis thrown out of mesh as the engine starts.

Another object is to provide such a device having novel provisions forpreventing the pinion from drifting away from its idle position whilethe engine is running.

Further objects and advantages will be apparent from the followingdescription taken in connection with the accompanying drawings in which:

Fig. 1 is a. side elevation partly in section of a preferred embodimentof the invention showing the parts in normal or idle position;

Fig. 2 is a similar view showing the parts in driving position;

Fig. 3 is a similar view showing the parts in the positions assumed whena pinion tooth abuts tooth of the flywheel gear;

Fig. 4 is a side elevation partly in section of a hollow screw shaft tobe attached to a power 50 shaft;

Fig. 5 is a similar view of a nut member to threaded thereon;

Fig. 6 is an end view of the nut member shown in Fig. 5;

Fig. 7 is a side elevation partly in section of a nut member to bethreaded on the first nut member;

Fig. 8 is an end view of the second nut member;

Fig. 9 is a detail of a spring member operative to insure initialthreaded engagement of the screw shaft and first nut member; and

Fig. 10 is a section of said spring member taken substantially on theline 1010 of Fig. 9.

Referring first to Fig. 1 of the drawings, there is illustrated anengine starter drive including a power shaft 1 which may be the extendedarmature shaft of a starting motor not shown. A driving member in theform of a pinion 2 is journalled on the power shaft 1 with freedom forlongitudinal movement into and out of meshing engagement with a memberof an engine to be startedsuch as a flywheel gear 3.

Means are provided for traversing the pinion 2 into and out ofengagement with the engine gear 3 and for rotating said pinion includingtwo inclined connections in series. The first inclined connectionincludes a hollow shaft 4' provided with threads 5 for a portion of itslength (Fig.

4) suitably fixed to the power shaft 1 as by means of the key 6 and astud 7 threaded into a collar 8 mounted on the, end of the screw shaft;and a nut member 9 mounted on the hollow shaft 4 and provided withinternal threads 11- adapted to cooperate with the threads 5 on saidshaft. Stop means in the form of shoulders 12 are provided on said shaftfor limiting longitudinal motion of the nut member 9 thereon in onedirection, and the collar 8"serves to limit motion thereof in theopposite direction. The threads 5 terminate a sufficient distance fromthe collar 8 to allow the nut to run off said threads and rotate freelyon the smooth portion of shaft 4 adjacent the collar 8.

Means are provided for normally retaining the nut 9 in its idle positionon said smooth portion of shaft 4 as indicated in Fig. 1. As thereshown, this means takes the form of a light spring 13 arranged to hearat one end against said nut member and at the other end against anabutment ring 14 seated against a shoulder 15 adja- 10o cent the end ofthe shaft 4. The shoulders 12 and 15 on shaft 4 are preferably providedby forming said shaft with stepped portions as indicated in dotted linesin Fig.- 4 before the threads 5 are hobbed on said shaft.

The second inclined connection includes a second nut member 16 arrangedto be threaded on the first nut member with a comparatively steeplypitched thread as best shown in Figs. 5 and 7, the external threadon thenut 9 being indicated 110 at 17 and the internal thread in the nut 16being indicated at 18.

In order to complete the traversing and rotating connection between theshaft 1 and pinion 2, nut member 16 is slidably mounted in a barrel orshell member 19 as by means of radial lugs 21 on said nut memberengaging the slots 22 of said shell; and the shell 19 is fixed to thepinion 2 at one end as by means of inwardly extending lugs 23 adapted tofit between the rear ends of the pinion teeth and suitably held inposition as by spinning over the hubof the pinion as indicated at 24.The opposite end of the shell 19 is closed by means of a cap 25 threadedthereto as indicated at 26 and forming an abutment for the nut members 9and 16.

Means are provided for cooperating with the second inclined connectionto provide a yielding driving connection to the pinion in the form of aspring 27 hearing against the nut member 16 at one end and against thefront end 28 of the shell 19, whereby the shifting movement of saidsecond inclined connection is yieldably limited and said nut member isnormally retained at the rearward limit of its travel in the shell 19against the cap 25. A cushioning element 29 may be provided within thecap 25 if so desired in order to render the operation of the device morequiet.

Means are provided for ensuring engagement of the shifting connection onactuation of the power shaft by urging the inner nut member 9 intoinitial engagement with the threads 5. As here shown, this means is inthe form of an elastic spider 31 (Figs. 9 and 10) which is arranged tobe loosely mounted on the shaft 4 within the shell 19 adjacent the endof the hollow shaft 4. The spider 31 is provided with resilient arms 32adapted to bear against the end 28 of the shell 19 when the parts are inidle position as shown in Fig. 1 and thereby cause the cap 25 of saidshell to urge the nut member 9 against the ends of the threads 5.

In the operation of the device, starting with the parts in the positionsshown in Fig. 1, rotation of the power shaft 1 in the direction of thearrow causes the inner nut member 9 to enter the threads 5 on the hollowshaft 4 and to be traversed thereby by reason of its inertia and theinertia of the parts associated therewith, until the end of said nutmember engages the stop shoulders 12 on said shaft. The entire pinionassembly including the nut members 9 and 16, the shell 19 and pinion 2is thus shifted longitudinally until the pinion 2 is meshed with theflywheel gear 3, this meshing position being defined by the shoulders 12on the hollow shaft 4 as illustrated in Fig. 2. Further rotation of thepower shaft 1 is transmitted directly to the inner nut member 9 andthrough the inclined connection 17, 18 to the outer nut member 16. Thespring member 27 cooperates with said inclined connection to form ayielding driving connection with the pinion through the splinedconnection 21, 22 to the shell 19 fixed to said pinion, whereby theengine member 3 is rotated to crank the engine.

When the engine starts, the acceleration of the flywheel gear 3 istransmitted to the pinion 2 causing the nut members 16 and 9 to overrunthe hollow shaft 4. whereby'the nut member 9 is traversed back to itsidle position, carrying the pinion assembly therewith by virtue of itsengagement with the cap 25. When the nut 9 reaches its idle position itruns off the ends of the threads 5, thereupon rotating freely on thesmooth portion of the shaft 4. Rebounding of the pinion toward theengine gear by reason of impact when thrown out of mesh therewith isthus efiectively prevented. The engaging surfaces 33 and 34 on said nutmember and on the collar 8 are preferably inclined at such an angle asto create suitable friction upon the engagement thereof to dissipate themomentum of the pinion assembly. When the spinning of the pinionassembly has ceased, the spider 31 functions to hold the nut member 9against the ends of the threads 5 and causes proper engagement with saidthreads upon actuation of the power shaft 1 as previously described.

If during the meshing movement of the pinion 2 a tooth thereof shouldabut end to end with a tooth of the flywheel gear 3, longitudinalmovement of the pinion 2 and outer nut member 16 is obstructed. Underthese circumstances further longitudinal movement of the inner nutmember 9 causes the second inclined connection to cooperate with theshell 19 to provide means for indexing the pinion. In this operation theouter nut member 16 is rotated slightly due to the high pitch threads17, 18 and this rotation is transmitted through the shell 19 to indexthe pinion 2 into proper registry with the teeth of the flywheel gear,whereupon meshing and cranking take place as usual.

It will be noted that during this indexing action, the pinion 2 ispressed against the flywheel gear 3 by the spring 27 which is compressedby the longitudinal component of the forces applied to the outer nutmember 16 from the inner nut 9 as indicated in Fig. 3. This compressionof the spring 27 causes the pinion 2 to be snapped into initialengagement with the flywheel gear as soon as proper registry takesplace, whereby the possibility of a milling action of the pinion teethon the flywheel gear is prevented. It will be noted that by reason ofthe steep inclination of the outer threads 17, 18, the indexing actionas above descr bed will take place without the necessity of building upa heavy longitudinal pressure. It W111 also be understood that this samefeature allows the use of a comparatively small and light spring 27since the longitudinal component of the cranking torque transmittedthrough said inclined connection is comparatively small.

Although but one embodiment of this inven t10n has been shown anddescribed in detail, it will be understood that various changes may bemade in the construction and arrangements of the parts without departingfrom the spirit of the invention as defined in the claims appendedhereto.

What is claimed is:

1. In an engine starter drive a power shaft, a driving member, means forshifting and rotating said driving member from said shaft including afirst inclined-connection, a second inclined connection includinglongitudinally movable members between the driving member and the firstinclined connection, and means whereby obstruction of the longitudinalmovement of the driving member during the shifting movement of the firstinclined connection causes relative movement of the elements of saidsecond inclined connection to index the driving member.

2. In an engine starter, drive, a power shaft, a driving member, meansfor shifting and rotating said driving member from said shaft includinga first inclined connection, a second inclined connection including apair of longitudinally movable elements in series therewith, and meansconnecting one of the elements of said second inclined connection tosaid driving member whereby obstruction of the meshing movement of thedriving member restricts the longitudinal movement of said element, andfurther shifting movement of the cooperating element of the secondinclined connection by the first inclined connection causes indexing ofthefirst mentioned element and said driving member.

3. In an engine starter drive, a power shaft, a driving member slidablyjournalled thereon and means for traversing and rotating said drivingmember from said shaft including a member connected with said shaft forautomatic traversal thereon toward a member of an engine to be started,a second member so connected with said first member that relativelongitudinal movement causes relative rotation therebetween, meansconnecting said driving member to said second member for rotationtherewith and yielding means for opposing relative longitudinal movementof said second member and driving member.

4. In an engine starter drive, a power shaft, a driving memberjournalled thereon, means for automatically traversing the drivingmember into and out of engagement with a member of an engine to bestarted including an inclined connection of relatively low pitch and ayielding driving connection for rotating the pinion from the shaftincluding an inclined connection of relatively high pitch.

5. In an engine starter drive, a power shaft, a driving memberjournalled thereon, means for automatically traversing the drivingmember into and out of engagement with a member of an engine to bestarted including an inclined connection of relatively low pitch andmeans for positively limiting relative longitudinal movement of theparts thereof in the engaging direction, and a yielding drivingconnection for rotating the pinion from the shaft including an inclinedconnection of relatively high pitch and means for yieldingly limitingrelative longitudinal movement of the parts thereof in the'drivingdirec-' tion.

6. In an engine starter drive, a power shaft, a driving member slidablyjournalled thereon and means for traversing and rotating said drivingmember from said shaft including a nut member having a threadedconnection with said shaft of a relatively low pitch, a second nutmember having a threaded connection to the first nut member ofrelatively high pitch, and means for transmitting longitudinal movementand rotary movement from the second nut member to said driving member.

7. In an engine starter drive, a power shaft, 9.

'- driving member slidably journalled thereon and means for traversingand rotating -said driving member from said shaft including a nut memberhaving a threaded connection with said shaft of a relatively low pitchand a stop for positively limiting longitudinal movement of the nut onsaid shaft in one direction, a second nut member having a threadedconnection to the first nut member of relatively high pitch and yieldingmeans for opposing longitudinal movement of said second nut on the firstnut.

8. In an engine starter drive, a power shaft, a driving member, meansfor shifting said driving member into and out of engagement with anengine member and for rotating said driving member to crank said engineincluding/two inclined connections in series, one of said connec-- tionsoperating through the other connection to shift the driving member andbeing automatically disconnectable to allow the driving member tooverrun.

9. In an engine starter drive, a power shaft, a driving member, meansfor shifting said driving member into and out of engagement with anengine member and for rotating said driving member to crank said engineincluding two inclined connections in series, one of said connectionsoperating through the other connection to shift the driving member andbeing automatically disconnectable to allow the driving member tooverrun and means for insuring reengagement of said shifting connectionon reactuation of the power shaft.

10. In an engine starter drive, a power shaft, a driving member, meansfor shifting said driving member into and out of engagement with anengine member and for rotating said driving member to crank said engineincluding two inclined connections in series, one of said connectionsoperating through the other connection to shift the driving member andbeing automatically disconnectable to allow the drivingmember to overrunand resilient means cooperating with said other inclined connection toform a yielding driving connection to said driving member.

11. An engine starter drive including a shaft, a pinion mounted thereonfor movement into and out of mesh with an engine gear, a member having asplined connection with the pinion, yielding means for transmittingmeshing movement from said member to said pinion, a cooperating memberhaving an inclined connection with said first member such that relativelongitudinal movement causes relative rotation therebetween, means formoving said cooperating member longitudinally in a direction to mesh thepinion and for thereafter rotating the same, said yielding meanscooperating with said inclined connection to form a yielding drivingconnection for said pinion.

12. An engine starter drive including a shaft, a pinion'mounted thereonfor movement into and out of mesh with an engine gear, a member having asplined connection with the pinion, a yielding means for transmittingmeshing movement from said member to said pinion, a cooperating memberhaving an inclined connection with said first member such that relativelongitudinal movement causes relative rotation therebetween, means formoving said cooperating member longitudinally in a direction to mesh thepinion and for thereafter rotating the same, said yielding meanscooperating with said inclined connection to form a yielding drivingconnection from said pinion, said inclined connection being so formedthat obstruction of the meshing movement of the pinion causes the secondmember to rotate the first member while pressing it longitudinallyagainst said yielding means.

13. In an engine starter drive, a power shaft, a pinion, means forshifting said pinion into and out of mesh with an engine gear and forrotating said pinion to crank said engine including a nut member havinga threaded connection to said shaft, a second member having an inclinedconnection with the nut member of a comparatively high pitch, a shiftingand driving connection between said second member and said pinion, saidnut member being arranged to shift the second member to move the pinioninto and out of mesh with the engine gear and to rotate said secondmember to index said pinion by virtue I 14. In an engine starter drive,a power shaft, a pinion, means for shifting said pinion into and out ofmesh with an engine gear, andfor rotating said pinion to crank saidengine including a nut member having a threaded connection to saidshaft, a second member having an inclined connection with the nut memberof a comparatively high pitch, a shifting and driving connection betweensaid second member and said pinion, said nut member being arranged toshift the second member to move the pinion into and out of mesh with theengine gear and to rotate said second member to index said pinion byvirtue of said inclined connection in case of tooth abutment betweensaid pinion and gear, said nut member being arranged to run off itsthreaded connection and allow the pinion to overrun after being returnedto its idle position.

15. In an engine starter drive, a power shaft, a pinion journalleddirectly thereon and adapted to engage and drive a gear of an engine tobe started, means actuated by said power member for shifting said pinioninto driving position and thereafter forming a positive rotaryconnection in the line of drive'to said pinion, said shifting andconnecting means including means interposed between the positive rotaryconnection and the pinion for indexing said pinion in case of toothabutment with the engine gear, and means cooperating with said indexingmeans to form a yielding rotary connection in said line of drive.

16. An engine starter drive including a power shaft, a pinion freelyjournalled thereon for longitudinal movement into and out of mesh withan engine gear, a nut having a threaded connection with said shaft, ashifting and driving connection from said nut to said pinion, meanslimiting the travel of said nut in a direction to mem the pinion, saidthreaded connection terminating at a point just short of the idleposition of said nut, and yielding means urging said nut into initialthreaded relation with said shaft.

17. An engine starter drive including a power shaft, a pinion freelyjournalled thereon for longitudinal movement into and out of mesh withan engine gear, a nut having a threaded connection with said shaft, ashifting and driving connection from said nut to said pinion, meanslimiting the travel of said nut in a direction to mesh the pinion, saidshifting and driving connection including a second nut member threadedto the first nut member with a relatively high pitch thread wherebylongitudinal movement of the first nut member relatively thereto causesindexing of said second nut and pinion. I

18. An engine starter drive including a power shaft, a pinion freelyjournalled thereon for longitudinal movement into and out of mesh withan engine gear, a nut having'a threaded connection with said shaft, ashifting and driving connection from said nut to said pinion, meanslimiting the travel of said nut in a direction to mesh the pinion, saidshifting and driving connection including a second nut member threadedto the first nut member with a relatively high pitch thread, and meansfor yieldingly resisting longitudinal movement of the second nut memberwhen the pinion is in driving position and cooperating therewith to forma yielding driving connection for the pinion.

MAURICE P. WHITNEY.

